Anti-inflammatory plant flavonoids and cellular action mechanisms

Chrysophanol, Physcion, Hesperidin and Curcumin Modulate the Gene Expression of Pro-Inflammatory Mediators Induced by LPS in HepG2: In Silico and Molecular Studies

Hepatitis is an inflammatory condition that can develop hepatocellular carcinoma. Traditional medicine has always been the pillar of medical practice. However, it became less compatible with the current understanding of the diseases and the possible treatment. Therefore, in silico tools could be utilized for building the bridge between the legacy of the past and the current medical approaches allowing access to new therapeutic discoveries. In this work, a Chinese traditional medicine database was screened using structure-based virtual screening to identify molecules that could inhibit p38 alpha mitogen-activated protein kinase (MAPK). Out of the identified compounds, four selected compounds: chrysophanol, physcion, curcumin and hesperidin were isolated from their respective sources and their structures were confirmed by spectroscopic methods. These compounds decreased the gene expression of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and interleukin-1beta (IL-1β) in lipopolysaccharide (LPS) induced inflammation in a hepatocellular carcinoma cell line (HepG2) in a dose-dependent manner. The molecular docking study revealed the specificity of these compounds towards p38 MAPK rather than other MAPKs. In conclusion, the molecular and in silico studies suggest that the isolated compounds could be a potential treatment for hepatitis by resolving inflammation controlled by MAPKs, thus limiting the development of further complications and lower side effects.

Flavonoid VI-16 protects against DSS-induced colitis by inhibiting Txnip-dependent NLRP3 inflammasome activation in macrophages via reducing oxidative stress

Emerging evidence suggests that NLRP3 inflammasome was associated with various kinds of immunological diseases including colitis. However, there are few drugs targeting inflammasomes in the treatment of colitis. Several flavonoids have been found to affect the inflammasome pathway, but the mechanism is still confusing. Here we report that VI-16, a synthetic flavonoid compound, exerts potent anti-inflammatory effects on macrophages in DSS-induced colitis mice, which intervened in the activation of NLRP3 inflammasome without affecting intestinal epithelial cells. However, the protection of VI-16 against DSS-induced colitis was dependent on NLRP3 expression in hematopoietic cells. Furthermore, this inhibitory effect of VI-16 was found to be at least partially achieved by decreasing the mitochondrial ROS generation without affecting autophagy. Further studies confirm that VI-16 inhibits the binding of Txnip to NLRP3 by reducing oxidative stress and ultimately inhibits NLRP3 inflammasome. This demonstrates the ability of VI-16 to inhibit the NLRP3 inflammasome activation and its potential use in the treatment of inflammatory bowel disease.

Bee Pollen Extracts Modulate Serum Metabolism in Lipopolysaccharide-Induced Acute Lung Injury Mice with Anti-Inflammatory Effects

Bee pollen (BP) collected from different floras possesses various potential bioactivities, but the mechanism-related research on anti-inflammatory effects is limited. Here, three types of BP originating from Camellia sinensis L. (BP-Cs), Nelumbo nucifera Gaertn. (BP-Nn), and Brassica campestris L. (BP-Bc) were assessed using molecular and metabolomics methods to determine their anti-inflammatory effects. The differences in polyphenolic abundance of three types of BP extracts were determined by HPLC-DAD/Q-TOF-MS. In vitro anti-inflammatory effects of three BP extracts were evaluated in a lipopolysaccharide (LPS)-induced RAW 264.7 cells model. BP-Cs extract with the most abundant polyphenols was found to be the most effective in reducing inflammation by downregulating inflammatory-related genes expression and blocking the activation of MAPK and NF-κB signaling pathways. Polyphenol-rich BP-Cs was further evaluated for their in vivo anti-inflammatory effect in a LPS-induced acute lung injury mouse model. An UPLC-Q-TOF/MS-based metabolomics approach was applied to analyze metabolite changes in mouse serum. Weshowed that the pretreated BP-Cs extract alleviated inflammation and regulated glycerophospholipid metabolism significantly. Our findings provide a foundation for developing and justifying BP as a potential anti-inflammatory ingredient in functional foods or nutraceutical formulations.

Chemical fingerprint, acute oral toxicity and anti-inflammatory activity of the hydroalcoholic extract of leaves from Tocoyena formosa (Cham. & Schlecht.) K. Schum

Inflammation is a protective response of the organism against damaging agents, this process is considered beneficial, however in some situations, this response can be damage when exacerbated effect are present. This claim objective to evaluate the qualitative and quantitative chemical profile, acute toxic and anti-inflammatory effects of the hydroalcoholic extract of leaves from Tocoyena formosa (Cham. & Schlecht.) K. Schum. (HELTF). Quantitative and qualitative phytochemical analysis was performed by HPLC-DAD and colorimetric assay. The topical anti-inflammatory activity was determined in Croton oil-induced ear edema assay and systemic activity was performed in vascular permeability, paw edema induced by carrageenan and dextran. Phytochemical analysis of leaves from HELTF showed presence of tannin, flavonoid, saponins an other that confirmed by HPLC analysis. The extract did not cause significant with LD₅₀ greater than 5000 mg/kg and did not promote significate reduction in topical inflammatory process. However, HELTF demonstrate significant reduction of paw edema induced by carrageenan and dextran. The HELTF (200 mg/kg) reduced the protein/cell migration in the intradermal carrageenan-induced inflammation. Our results demonstrated that the first time the chemical profile and describe the effective action in systemic anti-inflammatory, antiedematogenic activity and low acute toxicity. This activity presents, supporting its traditional use. However, new studies are necessary for the detection and clarification of the possible mechanism of action.

Bergamot (Citrus bergamia, Risso): The Effects of Cultivar and Harvest Date on Functional Properties of Juice and Cloudy Juice

Reggio Calabria province (South Italy) is known for being almost the only area of cultivation of the bergamot fruit, grown principally for its essential oil, but today much studied for the health benefits of its juice. The biometrics and physico-chemical properties of the three (Citrus bergamia Risso) existing genotypes namely Castagnaro, Fantastico and Femminello were studied during fruit ripening from October to March. Castagnaro cultivar had the biggest and heaviest fruit during this harvest period. °Brix (7.9-10.0), pH (2.2-2.8) and formol number (1.47-2.37 mL NaOH 0.1 N/100 mL) were shown to be influenced by both the genotype and harvest date. Titratable acidity (34.98-59.50 g/L) and vitamin C (ascorbic acid) (341-867 g/L) decreased during fruit ripening. The evolution of flavonoids such as neoeriocitrin, naringin, neohesperidin, brutieridin and melitidin was studied both in bergamot juice and in the bergamot cloudy juice which is the aqueous extract of bergamot during fruit processing. Bergamot cloudy juice contained a higher quantity of flavonoids compared to the juice. This study gives important information regarding the cultivar and the harvest date for producers who want to obtain the highest juice quantity or the highest juice quality from the bergamot fruit.

Design of balanced COX inhibitors based on anti-inflammatory and/or COX-2 inhibitory ascidian metabolites

The aim of this study was to design and synthesize COX-1/COX-2 balanced inhibitors incorporating the structural motifs of anti-inflammatory ascidian metabolites. We designed a series of substituted indole analogs that incorporate the key structures of the ascidian metabolites, herdmanines C and D. The synthesized analogs were tested for their inhibitory activity against COX-1 and COX-2, and compound 5m, which displayed balanced inhibition, was further evaluated for in vitro anti-inflammatory activity. Compound 5m suppressed the expression of pro-inflammatory factors, including iNOS, COX-2, TNF-α, and IL-6 in LPS-stimulated murine RAW264.7 macrophages. The reduction of PGE₂, NO, and ROS was also observed, together with the suppression of NF-κB, IKK, and IκBα phosphorylation. Our results characterized 5m as a COX-1/COX-2 balanced inhibitor that subsequently caused ROS inhibition and NF-κB suppression, and culminated in the suppression of iNOS, COX-2, TNF-α, and IL-6 expression.

Polyphenols in the treatment of autoimmune diseases

In addition to protecting body from infections and diseases, the immune system produces auto-antibodies that can cause complex autoimmune disorders, such as Type I diabetes, primary biliary cirrhosis, rheumatoid arthritis, and multiple sclerosis, to name a few. In such cases, the immune system fails to recognize between foreign agents and its own body cells. Different factors, such as genetic factors (CD25, STAT4), epigenetic factors (DNA methylation, histone modifications) and environmental factors (xenobiotics, drugs, hormones) trigger autoimmunity. Glucocorticoids, non-steroidal anti-inflammatory drugs (NSAIDs), immunosuppressive and biological agents are currently used to manage autoimmune diseases of different origins. However, complete cure remains elusive. Many dietary and natural products including polyphenols have been widely studied as possible alternative treatment strategies for the management of autoimmune disorders. Polyphenols possess a wide-range of pharmacological and therapeutic properties, including antioxidant and anti-inflammatory activities. As immunomodulatory agents, polyphenols are emerging pharmaceutical tools for management of various autoimmune disorders including vitiligo, ulcerative colitis and multiple sclerosis (MS). Polyphenols activate intracellular pathways such as arachidonic acid dependent pathway, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway, mitogen-activated protein kinases (MAPKs) pathway, phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway and epigenetic modulation, which regulate the host's immune response. This timely review discusses putative points of action of polyphenols in autoimmune diseases, characterizing their efficacy and safety as therapeutic agents in managing autoimmune disorders.

Isozymes inhibited by active site blocking: versatility of calcium indifferent hesperidin binding to phospholipase A2 and its significance

sPLA₂ is released under inflammatory conditions from neutrophils, basophils and T-cells. They cleave the cellular phospholipids leading to the release of arachidonic acid and there by provide intermediates for biosynthesis of inflammatory mediators. The focus of this study is on the interaction of hesperidin, a natural flavonoid with Group IB, IIA, and V and X isozymes of sPLA₂. Affinity of hesperidin towards PLA₂ isozymes was analyzed through enzymatic studies and molecular modeling. The experiments showed that hesperidin competitively inhibited PLA₂ with IC₅₀ of 5.1 µM. Molecular modeling studies revealed the association of hesperidin with the docking scores -6.90, -9.53, -5.63 and -8.29 kcal for isozymes Group IB, IIA, V and X of PLA₂ respectively. Their binding energy values were calculated as -20.25, -21.63, -21.66 and -33.43 kcal for the Group IB, IIA, V and X respectively. Structural model for Group V was made by homology modeling since no structural coordinates were available. Molecular dynamics studies were carried out to evaluate the structural stability of protein ligand complex. The analyses showed that hesperidin blocked the entry of the substrate to the active site of PLA₂ and it was indifferent to the differences of the isozymes. Hence, hesperidin might serve as lead for designing highly specific anti-inflammatory drugs directed to the PLA₂ isozyme specific to various diseases, with IC₅₀ value of therapeutic significance.

Flavonoids: Broad Spectrum Agents on Chronic Inflammation

Flavonoids are major plant constituents with numerous biological/pharmacological actions both in vitro and in vivo. Of these actions, their anti-inflammatory action is prominent. They can regulate transcription of many proinflammatory genes such as cyclooxygenase-2/inducible nitric oxide synthase and many cytokines/chemokines. Recent studies have demonstrated that certain flavonoid derivatives can affect pathways of inflammasome activation and autophagy. Certain flavonoids can also accelerate the resolution phase of inflammation, leading to avoiding chronic inflammatory stimuli. All these pharmacological actions with newly emerging activities render flavonoids to be potential therapeutics for chronic inflammatory disorders including arthritic inflammation, meta-inflammation, and inflammaging. Recent findings of flavonoids are summarized and future perspectives are presented in this review.

Emex spinosa (L.) Campd. ethyl acetate fractions effects on inflammation and oxidative stress markers in carrageenan induced paw oedema in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Emex spinosa (L.) Campd. (E. spinosa) locally known as "hillaioua" has always been used in folk medicine for the treatment of inflammation and pain. It is still being exploited by pharmaceutical companies for its potential remedial effects.

AIM OF THE STUDY

In this study, the effects of E. spinosa (L.) Campd. against acute inflammation, pain and oxidative damage were evaluated.

MATERIALS AND METHODS

Total phenols and flavonoids were evaluated. Anti-inflammatory and analgesic activities the E. spinosa ethyl acetate fractions of the aerial (Es EtOAc-AP) and underground (Es EtOAc-R) parts were assessed on carrageenan-induced paw oedema (100 mg/kg BW) and acetic acid-induced writhing response (50, 100 and 150 mg/kg BW), respectively. The E. spinosa fractions effects on oxidative stress markers and inflammatory parameters were determined. Gas chromatography-mass spectrometry (GC-MS) analysis was performed to identify various chemical components.

RESULTS

The ethyl acetate fractions were shown to be the most active thanks to their phenolic and flavonoid contents richness. Intraperitoneal administration of E. spinosa ethyl acetate fractions at 100 mg/kg BW, one hour before carrageenan injection, significantly inhibited the oedema formation by 89.31% and 97.7% for the aerial and underground parts respectively when compared to the reference drug "dexamethasone" (51.9%). Besides, a significant increase (p ≤ 0.001) of the dermal antioxidant enzymes (the superoxide dismutase (SOD)), catalase (CAT) and glutathione peroxidase (GPx) was observed five hours after carrageenan administration. The best restoration was obtained with Es EtOAc-R (82.04%, 93.55% and 93.55% respectively for SOD, CAT and GPx activities). Moreover, EtOAc-fractions treated mice proved their ability to restore both of CRP and fibrinogen (p < 0.001). In addition, E. spinosa EtOAc-fractions attenuated abdominal contractions (p < 0.05) by 71.69% and 82.41% for the aerial part and roots respectively at 150 mg/kg BW against 100% for dichlofenac sodium used as standard drug. The phytochemical analysis of Es EtOAc-AP and Es EtOAc-R by GC-MS may explain the obtained results. The analysis of the fractions demonstrated the presence of palmitic and linoleic acids known for their anti-inflammatory and analgesic capacities.

CONCLUSIONS

These findings explain the traditional use of E. spinosa in folk medicine and suggest that E. spinosa fractions could be a promising herbal drug.

The Flavone Luteolin, an Endocrine Disruptor, Relaxed Male Guinea Pig Gallbladder Strips

Background

Luteolin (3',4',5,7-tetrahydroxyflavone) is a flavone with a yellow crystalline appearance present in numerous plants such as broccoli, green chili, and carrot. Luteolin is considered to be an endocrine disruptor with potent estrogen agonist activity and potent progesterone antagonist activity. Luteolin has effects on smooth muscle. Luteolin relaxed guinea pig trachea smooth muscle as it inhibited both phosphodiesterase and reduced intracellular Ca²⁺. Luteolin also caused vasorelaxation in rat thoracic aorta smooth muscle by inhibiting intracellular Ca²⁺ release, inhibition of sarcolemmal Ca²⁺ channels, and activation of K⁺ channels. Luteolin or its glycosides from artichoke extracts may have an ameliorating effect on irritable bowel syndrome. The purpose of this study was to determine if luteolin had an effect on gallbladder motility.

Methods

An in vitro pharmacologic technique was utilized. Either cholecystokinin octapeptide (CCK) or KCl were used to induce tension in male guinea pig gallbladder strips maintained in Sawyer-Bartlestone chambers. Luteolin relaxed either the CCK- or KCl-induced tension in a concentration dependent manner. Various blockers were added to the chambers to determine which second messenger system(s) mediated the observed relaxation. Paired t-tests were used for statistical analysis. Differences between mean values of P < 0.05 were considered significant.

Results

Treatment of the gallbladder strips with luteolin prior to either KCl or CCK significantly (P < 0.001) decreased the amount of either KCl- or cholecystokinin-induced tension. The 2-aminoethoxydiphenylborane was used to ascertain if the release of intracellular Ca²⁺ mediated the luteolin-induced relaxation. It significantly (P < 0.001) decreased the amount of luteolin-induced relaxation. To ascertain if PKA mediated the luteolin-induced relaxation, PKA inhibitor 14-22 amide myristolated was used. It significantly (P < 0.01) reduced the amount of luteolin-induced relaxation. Neither KT5823, N^G-methyl-L-arginine acetate salt, genistein, tetraethylammonium, nor fulvestrant had a significant effect. To ascertain if PKC mediated the luteolin-induced relaxation, the PKC inhibitors bisindolymaleimide IV and chelerythrine Cl^- were used together. They had no significant effect.

Conclusions

Luteolin relaxed cholecystokinin- or KCl-induced tension by blocking extracellular Ca²⁺ entry as well as intracellular Ca²⁺ release. In addition, the actions of PKA are also involved in mediating the luteolin effect.

A review on traditional uses, phytochemistry and pharmacological activities of the genus Ballota

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Ballota L. (Lamiaceae) comprises 33 to 35 species distributed mainly in temperate and subtropical regions of the world. Some species have been used in folk medicine as antiemetic, antispasmodic, sedative agents, vermifuge, antihemorrhoid and also in treatment of cough, etc. AIM OF THIS REVIEW: This review article aims to provide organized information on the available traditional uses, phytochemical and pharmacological studies of the genus Ballota, and to obtain new insights for further researches.

MATERIALS AND METHODS

Electronic databases, including Web of Science, Science Direct, Google Scholar, Scopus, PubMed, and Springer Link were used as information sources. General web searches were carried out using Google and Yahoo search engines by applying related search terms. Additional information was derived from books and journals in English, Latin and Persian, and also Ph.D. theses and M.Sc. dissertations.

RESULTS

Terpenoids (particularly furanolabdane diterpenoids) and flavonoids were the main phytochemical classes identified in the extracts of Ballota species. Furanolabdane diterpenoids, e.g. ballonigrin, dehydrohispanolone, and hispanolone were reported in many species of Ballota. β-Caryophyllene, caryophyllene oxide, and germacrene D were found as the most common major compounds isolated from the essential oils of the genus Ballota. Sixty-four pharmacological studies conducted on cell lines, microorganisms, and animals were included in this review. Some species of Ballota exhibited various pharmacological activities, including promising antidepressant, anxiolytic, sedative-hypnotic, and antitussive activities in animal models. The pharmacological activities can be attributed to bioactive phytochemicals.

CONCLUSION

The genus Ballota is a valuable source of bioactive compounds with therapeutic potential in different diseases. Some pharmacological studies showed incomplete methodologies and ambiguous findings. Thus, the research designs of pharmacological studies based on traditional uses of Ballota species are strongly needed in cell lines and animal models. More in vitro and in vivo animal studies are required to confirm the safety, clarification of the effective doses, bioactive compounds, and the mechanisms of actions before future clinical studies.

Nutritional Relevance of Flavonoids in Disease Prevention

Flavonoids are not essential nutrients in that their absence from the diet does not produce deficiency conditions in animals and man. However, many have important similarities to pharmacological agents used in the treatment of disease. Their role as dietary components in disease prevention is less clear. Many potentially anti-carcinogenic and anti-atherogenic effects observed in cell cultures will not be of nutritional relevance unless flavonoids gain access to appropriate cellular sites. The bioavailability of flavonoids will depend on numerous factors including molecular structure, the amount consumed, the food matrix, degree of bioconversion in the gut and tissues, the nutrient status of the host and genetic factors. Moreover, extensive and rapid intestinal and hepatic metabolism of flavonoids suggests that the body may treat them as xenobiotic and potentially toxic compounds requiring rapid elimination. Consequently, in addition to potential health benefits, possible adverse effects of flavonoids in the diet also need to be considered when assessing their roles in the prevention of degenerative diseases.

Beneficial Effects of Citrus Flavonoids on Cardiovascular and Metabolic Health

The prevalence of cardiovascular disease (CVD) is increasing over time. CVD is a comorbidity in diabetes and contributes to premature death. Citrus flavonoids possess several biological activities and have emerged as efficient therapeutics for the treatment of CVD. Citrus flavonoids scavenge free radicals, improve glucose tolerance and insulin sensitivity, modulate lipid metabolism and adipocyte differentiation, suppress inflammation and apoptosis, and improve endothelial dysfunction. The intake of citrus flavonoids has been associated with improved cardiovascular outcomes. Although citrus flavonoids exerted multiple beneficial effects, their mechanisms of action are not completely established. In this review, we summarized recent findings and advances in understanding the mechanisms underlying the protective effects of citrus flavonoids against oxidative stress, inflammation, diabetes, dyslipidemia, endothelial dysfunction, and atherosclerosis. Further studies and clinical trials to assess the efficacy and to explore the underlying mechanism(s) of action of citrus flavonoids are recommended.

Effect of the flavonoid baicalin on the proliferative capacity of bovine mammary cells and their ability to regulate oxidative stress

Background

High-yielding dairy cows are prone to oxidative stress due to the high metabolic needs of homeostasis and milk production. Oxidative stress and inflammation are tightly linked; therefore, anti-inflammatory and/or natural antioxidant compounds may help improve mammary cell health. Baicalin, one of the major flavonoids in Scutellaria baicalensis, has natural antioxidant and anti-inflammatory properties in various cell types, but its effects on bovine mammary epithelial cells (BMECs) have not been investigated.

Methods

Explants from bovine mammary glands were collected by biopsy at the peak of lactation (approximately 60 days after the start of lactation) (n = three animals) to isolate BMECs corresponding to mature secretory cells. Cell viability, apoptosis, proliferative capacity and reactive oxygen species (ROS) production by BMECs were measured after increasing doses of baicalin were added to the culture media in the absence or presence of H₂O₂, which was used as an in vitro model of oxidative stress.

Results

Low doses of baicalin (1–10 µg/mL) had no or only slightly positive effects on the proliferation and viability of BMECs, whereas higher doses (100 or 200 µg/mL) markedly decreased BMEC proliferation. Baicalin decreased apoptosis rate at low concentrations (10 µg/mL) but increased apoptosis at higher doses. ROS production was decreased in BMECs treated with increasing doses of baicalin compared with untreated cells, and this decreased production was associated with increased intracellular concentrations of catalase and NRF-2. Irrespective of the dose, baicalin pretreatment attenuated H₂O₂-induced ROS production.

Discussion

These results indicate that baicalin exerts protective antioxidant effects on bovine mammary cells. This finding suggests that baicalin could be used to prevent oxidative metabolic disorders in dairy cows.

Potential Role of Flavonoids in Treating Chronic Inflammatory Diseases with a Special Focus on the Anti-Inflammatory Activity of Apigenin

Inflammation has been reported to be intimately linked to the development or worsening of several non-infectious diseases. A number of chronic conditions such as cancer, diabetes, cardiovascular disorders, autoimmune diseases, and neurodegenerative disorders emerge as a result of tissue injury and genomic changes induced by constant low-grade inflammation in and around the affected tissue or organ. The existing therapies for most of these chronic conditions sometimes leave more debilitating effects than the disease itself, warranting the advent of safer, less toxic, and more cost-effective therapeutic alternatives for the patients. For centuries, flavonoids and their preparations have been used to treat various human illnesses, and their continual use has persevered throughout the ages. This review focuses on the anti-inflammatory actions of flavonoids against chronic illnesses such as cancer, diabetes, cardiovascular diseases, and neuroinflammation with a special focus on apigenin, a relatively less toxic and non-mutagenic flavonoid with remarkable pharmacodynamics. Additionally, inflammation in the central nervous system (CNS) due to diseases such as multiple sclerosis (MS) gives ready access to circulating lymphocytes, monocytes/macrophages, and dendritic cells (DCs), causing edema, further inflammation, and demyelination. As the dearth of safe anti-inflammatory therapies is dire in the case of CNS-related disorders, we reviewed the neuroprotective actions of apigenin and other flavonoids. Existing epidemiological and pre-clinical studies present considerable evidence in favor of developing apigenin as a natural alternative therapy against chronic inflammatory conditions.

The medicinal uses, toxicities and anti-inflammatory activity of Polyalthia species (Annonaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Polyalthia is one of the largest and notable genera in Annonaceae family. Polyalthia species have been widely used in folklore medicine for the treatment of rheumatic fever, gastrointestinal ulcer and generalized body pain. Numerous in vitro and in vivo studies on Polyalthia Species have also corroborated the significant anti-inflammatory potential of its extracts and secondary metabolites.

AIM OF THE STUDY

This review is an attempt to assess the anti-inflammatory activity of Polyalthia species by giving critical appraisal and establishing evidences of their traditional uses. Moreover this review will highlight the lead compounds for future drug development that can serve as a potential anti-inflammatory drug with comparative efficacy and minimum side effects.

MATERIALS AND METHODS

An extensive literature review, focusing the anti-inflammatory potential of Polyalthia species was conducted using the following databases:PubMed, ScienceDirect, SpringerLink, Ovid, Scopus and ProQuest, as well as the locally available books, journals and relevant documents. The reference lists of retrieved papers were also searched for additional studies.

RESULTS

The Polyalthia species have shown significant anti-inflammatory activity through various mechanism of action. The most significant anti-inflammatory mechanism includes the inhibition of nuclear factor kappa B (NF-κB), prostaglandins (PGs), pro-inflammatory cytokines, inducible nitric oxide synthase (iNOS) and reactive oxygen species (ROS). The data suggests that hydroxycleroda-3,13-dien-15,16-olide and 16-oxocleroda-3,13-dien-15-oic acid, quercetin, rutin, spinasterol, α-spinasterol, goniothalamin and (-)-5-hydroxygoniothalamin are the most potent anti-inflammatory compounds from Polyalthia species with comparable IC₅₀ with positive controls.

CONCLUSIONS

Numerous pharmacological studies have supported the use of Polyalthia species against pain, rheumatic fever, haemorrhages and inflammation in traditional medicine. Flavonoids, diterpenoids, sterols and styrylpyrones from genus Polyalthia are the most significant class of compounds with potent anti-inflammatory activity. Secondary metabolites from these classes should be brought into further research to fill the gaps of knowledge in pharmacokinetics, pharmacodynamics, bioavailability, and toxicity in order to convert the pre-clinical results into clinical data for further investigation.

Black tea dressings - a rapidly effective treatment for facial dermatitis

Background: Facial dermatitis is a common dermatologic condition. It is usually treated with either topical corticosteroids or calcineurin inhibitors. However, the use of these drugs is limited by side effects, including skin atrophy, local immunosuppression and possible oncogenicity. Objective: The aim of the study was to evaluate the use of wet dressings with black tea for treating facial dermatitis. Methods: We performed a prospective, open, uncontrolled before-after study enrolling 22 patients with atopic or contact facial dermatitis who were treated with black tea dressings and an emollient cream over 6 days. Disease severity was assessed using the (1) Facial Eczema Area and Severity Index, (2) Visual analog scale for pruritus, (3) Investigator`s Global Assessment score, and (4) Patient's Self-Assessment score. The study was registered at www.ClinicalTrials.gov as NCT02941432. Results: A dramatic and highly significant reduction of all four disease activity scores occurred within the first 3 days of treatment and the patients continued to improve between days 3 and 6. No side effects were observed. Conclusion: Black tea dressings represent an effective treatment option for facial dermatitis. Its advantages include lack of side effects, low cost, and easy availability.

The phytochemical and anti-inflammatory studies of Dillenia suffruticosa leaves

The Dillenia suffruticosa leaves (Dilleniaceae), a folk medicine recommended in Southeast Asia for treating inflammation, were phytochemically studied for the first time and assessed for suppression of λ-carrageenan-induced paw oedema in rats. The crude methanolic extract orally administered at 5,000 mg/kg, displayed no toxicity and at 250 to 1,000 mg/kg significantly suppressed the paw oedema. Two-isolated triterpenoids, betulinic acid (1) and koetjapic acid (2) orally administered at 50 mg/kg, significantly reduced the paw oedema, (p < 0.001) and (p < 0.005) at the fourth h onwards to 47.36% ± 2.23 and 53.43% ± 7.09, respectively, from 95.90% ± 6.88 oedema induced by λ-carrageenan alone. 1 and the isolated flavonoids of vitexin (3), tiliroside (4), and kaempferol (5), displayed moderately more of cyclooxygenase (COX)-2 than COX-1 enzyme inhibition, whereas 2 was slightly more inhibition of COX-1. The in silico molecular docking studies provided support to the in vitro COX studies that the isolated compounds formed H-bonding with the amino acid residues at the COX-2 catalytic sites. The triterpenoids were bound to the peroxidase, possibly inhibiting the peroxidase reaction, whereas the flavonoids interacted more at the cyclooxygenase, resembling celecoxib, therefore providing evidences that these compounds were responsible for the anti-inflammatory properties of D. suffruticosa.

Cinnamon subcritical water extract attenuates intestinal inflammation and enhances intestinal tight junction in a Caco-2 and RAW264.7 co-culture model

Cinnamon is known to have several physiological effects; the effects of Cinnamomum japonicum Sieb. on anti-inflammation and tight junctions were investigated using the cellular intestinal inflammation model.

Simultaneous Optimization for Ultrasound-Assisted Extraction and Antioxidant Activity of Flavonoids from Sophora flavescens Using Response Surface Methodology

The ultrasonic-assisted extraction process and antioxidant activity of flavonoids from Sophora flavescens were investigated in this study. In order to optimize the extraction of flavonoids from Sophora flavescens, the influence of extraction time, methanol concentration, ultrasonic temperature, and solvent-to-material ratio was analyzed. Results showed that the extraction yields reached a maximum with the extraction time of 30 min, methanol concentration of 80%, temperature of 80 °C, and solvent-to-material ratio of 26 mL/g. The flavonoids were determined by HPLC, and the mean yields of trifolirhizin, formononetin, isoxanthohumol, maackiain, and kurarinone under the optimal conditions were 2.570, 0.213, 0.534, 0.797, and 3.091 mg/g, respectively. The evaluation of vitro antioxidant activity exhibited Sophora flavescens flavonoids had a strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical-scavenging ability with IC50 of 0.984 and 1.084 mg/g, respectively. These results indicate that ultrasonic-assisted extraction is an efficient approach for the selective extraction of flavonoids, and response surface methodology further optimized the extraction.

The nutraceutical potential of Lepidium sativum L. seed flavonoid-rich extract in managing metabolic syndrome components

The present study aimed to investigate the phytochemical and pharmacological identities of a Lepidium sativum L. (LS) flavonoid-rich extract and its beneficial effects on metabolic, hormonal, and histological status. Chemical screening, as well as high-performance liquid chromatography with diode-array detection (HPLC-DAD) identified high concentrations of the main flavonoid compounds in LS crude extract such as flavonols (quercetin, kaempferol), flavones (luteolin, apigenin), and especially flavanones (naringin, naringenin). Examinations of the biochemical and histopathological aspects showed the curative effects carried by LS flavonoid-rich extracts on high-fat diet-fed Wistar rats. In this study, we propose that these molecules probably exerted the bioactivity observed in the treated group through improving insulin sensitivity, dyslipidemia, inflammation, and pancreas β cell integrity. PRACTICAL APPLICATIONS: The LS seed is widely used in traditional medicine to treat hyperglycemia and inflammation. During the traditional mixture preparation, the thermal procedures could impair the bioactions of the most interesting group of LS phytoconstituants, flavonoids. In the present study, we propose an appropriate procedure to preserve those phytochemicals and suggest them as a substitute for the management of metabolic diseases. The dried LS extract showed an incredible set of effective flavonoids, which revealed hypoglycemic, hypolipidemic, anti-inflammatory, cytoprotective, and antidiabetic activities. Thus, LS flavonoids constitute a remarkable product to consider in pharmaceutical industry targeting diabetes and heart diseases. Due to their enormous antioxidant potential, the LS flavonoids could be also used in food engineering and cosmetic preparations. Their practical applications is however often limited by low solubility and stability in lipophilic media. Therefore, a modification of the flavonoid structure is possibly required.

Brazilian medicinal plants with corroborated anti-inflammatory activities: a review

CONTEXT

Inflammatory disorders are common in modern life, and medicinal plants provide an interesting source for new compounds bearing anti-inflammatory properties. In this regard, Brazilian medicinal plants are considered to be a promising supply of such compounds due to their great biodiversity.

OBJECTIVES

To undertake a review on Brazilian medicinal plants with corroborated anti-inflammatory activities by selecting data from the literature reporting the efficacy of plants used in folk medicine as anti-inflammatory, including the mechanisms of action of their extracts and isolated compounds.

METHODS

A search in the literature was undertaken by using the following Web tools: Web of Science, SciFinder, Pub-Med and Science Direct. The terms 'anti-inflammatory' and 'Brazilian medicinal plants' were used as keywords in search engine. Tropicos and Reflora websites were used to verify the origin of the plants, and only the native plants of Brazil were included in this review. The publications reporting the use of well-accepted scientific protocols to corroborate the anti-inflammatory activities of Brazilian medicinal plants with anti-inflammatory potential were considered.

RESULTS

We selected 70 Brazilian medicinal plants with anti-inflammatory activity. The plants were grouped according to their anti-inflammatory mechanisms of action. The main mechanisms involved inflammatory mediators, such as interleukins (ILs), nuclear factor kappa B (NF-κB), prostaglandin E2 (PGE2), cyclooxygenase (COX) and reactive oxygen species (ROS).

CONCLUSIONS

The collected data on Brazilian medicinal plants, in the form of crude extract and/or isolated compounds, showed significant anti-inflammatory activities involving different mechanisms of action, indicating Brazilian plants as an important source of anti-inflammatory compounds.

Amentoflavone Induces Autophagy and Modulates p53

Objective

Amentoflavone is the main component of Selaginella tamariscina widely known as an oriental traditional medicinal stuff that has been known to have a variety of medicinal effects such as the induction of apoptosis, anti- metastasis, and anti-inflammation. However, the effect of amentoflavone on autophagy has not been reported until now. The aim of this study was to investigate whether amentoflavone has a positive effect on the induction of autophagy related to cell aging.

Materials and Methods

In this experimental study, the aging of young cells was induced by the treatment with insulin- like growth factor-1 (IGF-1) at 50 ng/mL three times every two days. The effect of amentoflavone on the cell viability was evaluated in A549 and WI-38 cells using 3-(4,5-dimethyl-2-yl)-2,5- diphenyl tetrazolium bromide (MTT) assay. The induction of autophagy was detected using autophagy detection kit. The expression of proteins related to autophagy and IGF-1 signaling pathway was examined by western blot analysis and immunofluorescence assay.

Results

First of all, it was found that amentoflavone induces the formation of autophagosome. In addition, it enhanced the expression level of Atg7 and increased the expression levels of Beclin1, Atg3, and LC3 associated with the induction of autophagy in immunofluorescence staining and western blot analyses. Moreover, amentoflavone inhibited the cell aging induced by IGF-1 and hydrogen peroxide. In particular, the levels of p53 and p-p21 proteins were increased in the presence of amentoflavone. Furthermore, amentoflavone increased the level of SIRT1 deacetylating p53.

Conclusion

Our results suggest that amentoflavone could play a positive role in the inhibition of various diseases associated with autophagy and the modulation of p53.

Flavonoid biosynthetic pathways in plants: Versatile targets for metabolic engineering

Plants, fungi, and microorganisms are equipped with biosynthesis machinery for producing thousands of secondary metabolites. These compounds have important functions in nature as a defence against predators or competitors as well as other ecological significances. The full utilization of these compounds for food, medicine, and other purposes requires a thorough understanding of their structures and the distinct biochemical pathways of their production in cellular systems. In this review, flavonoids as classical examples of secondary metabolites are employed to highlight recent advances in understanding how valuable compounds can be regulated at various levels. With extensive diversity in their chemistry and pharmacology, understanding the metabolic engineering of flavonoids now allows us to fine-tune the eliciting of their production, accumulation, and extraction from living systems. More specifically, recent advances in the shikimic acid and acetate biosynthetic pathways of flavonoids production from metabolic engineering point of view, from genes expression to multiple principles of regulation, are addressed. Specific examples of plants and microorganisms as the sources of flavonoids-based compounds with particular emphasis on therapeutic applications are also discussed.

The Immunomodulatory and Anti-Inflammatory Role of Polyphenols

This review offers a systematic understanding about how polyphenols target multiple inflammatory components and lead to anti-inflammatory mechanisms. It provides a clear understanding of the molecular mechanisms of action of phenolic compounds. Polyphenols regulate immunity by interfering with immune cell regulation, proinflammatory cytokines' synthesis, and gene expression. They inactivate NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) and modulate mitogen-activated protein Kinase (MAPk) and arachidonic acids pathways. Polyphenolic compounds inhibit phosphatidylinositide 3-kinases/protein kinase B (PI3K/AkT), inhibitor of kappa kinase/c-Jun amino-terminal kinases (IKK/JNK), mammalian target of rapamycin complex 1 (mTORC1) which is a protein complex that controls protein synthesis, and JAK/STAT. They can suppress toll-like receptor (TLR) and pro-inflammatory genes' expression. Their antioxidant activity and ability to inhibit enzymes involved in the production of eicosanoids contribute as well to their anti-inflammation properties. They inhibit certain enzymes involved in reactive oxygen species ROS production like xanthine oxidase and NADPH oxidase (NOX) while they upregulate other endogenous antioxidant enzymes like superoxide dismutase (SOD), catalase, and glutathione (GSH) peroxidase (Px). Furthermore, they inhibit phospholipase A2 (PLA2), cyclooxygenase (COX) and lipoxygenase (LOX) leading to a reduction in the production of prostaglandins (PGs) and leukotrienes (LTs) and inflammation antagonism. The effects of these biologically active compounds on the immune system are associated with extended health benefits for different chronic inflammatory diseases. Studies of plant extracts and compounds show that polyphenols can play a beneficial role in the prevention and the progress of chronic diseases related to inflammation such as diabetes, obesity, neurodegeneration, cancers, and cardiovascular diseases, among other conditions.

Hydroalcoholic Extract and Ethyl Acetate Fraction of Bixa orellana Leaves Decrease the Inflammatory Response to Mycobacterium abscessus Subsp. massiliense

The incidence of infections caused by rapidly growing mycobacteria (RGM), especially Mycobacterium abscessus subsp. massiliense (Mabs), is increasing worldwide. Severe infections are associated with abscess formation and strong inflammatory response. This study evaluated the antimicrobial and anti-inflammatory activities of a hydroalcoholic extract (BoHE) and ethyl acetate fraction (BoEA) of Bixa orellana leaves. Antimicrobial activity was evaluated by broth microdilution to determine the minimum inhibitory (MIC) and the minimum bactericidal (MBC) concentrations. Cytotoxicity was evaluated using erythrocytes and RAW 264.7 cells. Nitric oxide (NO) was assayed in stimulated RAW 264.7 cells, and inflammatory cell migration and acute toxicity were evaluated in a Mabs-induced peritonitis mouse model. The compounds present in BoEA were identified by high performance liquid chromatography and mass spectrometry (HPLC-MS). The MIC and MBC values were 2.34 mg/mL and 37.5 mg/mL for BoHE and 0.39 mg/mL and 6.25 mg/mL for BoEA. The extracts did not induce significant toxicity in erythrocytes and RAW 264.7 cells. High levels of NO induced by Mabs were decreased by treatment with both extracts. The anti-inflammatory activity was confirmed in vivo by significant reduction of the cell migration to the peritoneum following BoHE and BoEA pretreatment. Animals treated with BoHE or BoEA did not show signs of acute toxicity in stomach, liver, and kidney. The chemical characterization of BoEA (the most active extract) revealed that kaempferol-3-O-coumaroyl glucose is its major component. The extract of B. orellana may be effective for treating infections caused by Mabs.

Fruit Bagasse Phytochemicals from Malpighia Emarginata Rich in Enzymatic Inhibitor with Modulatory Action on Hemostatic Processes

Agro-industrial wastes are promising sources of phytochemicals for the development of products to be used in health promotion and maintenance. In this study, extracts from acerola bagasse (AB) were characterized by HPLC, and evaluated according to its modulatory action on phospholipases A₂ and proteases involved in processes such as inflammation and blood clotting. Snake venoms were used as biological tools once they have high functional and structural homology between their enzymes and human enzymes. Two types of extracts were prepared from AB: aqueous and methanolic. These extracts, evaluated at different proportions (venom:extract, w:w), significantly inhibited the phospholipase activity induced by the venoms of Bothrops moojeni, Bothrops atrox (11% to 31%), and Crotalus durissus terrificus (C. d. t.) (11% to 19%). The hemolytic activity induced by the venoms of B. moojeni and C. d. t. was better inhibited by the methanolic extract (inhibition between 23% and 48%). Thrombolysis induced by the venoms of B. moojeni and C. d. t. was inhibited by both extracts, with inhibition ranging from 13% to 63% for the aqueous extract, and from 12% to 92% for the methanolic one. Both extracts increased the time of coagulation induced by the venoms of B. moojeni and Lachesis muta muta in 26 and up to 68 s. These inhibitory actions were related to the following phenolic compounds present in the extract of AB: gallic acid, catechin, epigallocatechin gallate, epicatechin, syringic acid, p-coumaric acid, and quercetin. Additional studies are needed to confirm their potential use for nutraceutical purposes. PRACTICAL APPLICATION: Agro-industrial wastes are promising sources of phytochemicals for the development of products that can be used by pharmaceutical, cosmetics, and food industries. Studies report the use of the acerola bagasse extract in health improvement. However, its toxic-pharmacological characterization is still scarce. In this study, the extracts of acerola bagasse presented phenolic compounds that can modulate the activity of enzymes such as phospholipases A₂ and proteases that act on the coagulant/anticoagulant and thrombotic/thrombolytic activities and the break of phospholipids, decreasing the inflammation and platelet aggregation. Although the in vivo effects of the extracts are not fully understood, this study shed light upon the possibilities of their usage.

Anti-senescence compounds: A potential nutraceutical approach to healthy aging

The desire of eternal youth seems to be as old as mankind. However, the increasing life expectancy experienced by populations in developed countries also involves a significantly increased incidence of the most common age-related diseases (ARDs). Senescent cells (SCs) have been identified as culprits of organismal aging. Their number rises with age and their senescence-associated secretory phenotype fuels the chronic, pro-inflammatory systemic state (inflammaging) that characterizes aging, impairing the regenerative ability of stem cells and increasing the risk of developing ARDs. A variegated class of molecules, including synthetic senolytic compounds and natural compounds contained in food, have been suggested to possess anti-senescence activity. Senolytics are attracting growing interest, and their safety and reliability as anti-senescence drugs are being assessed in human clinical trials. Notably, since SCs spread inflammation at the systemic level through pro-oxidant and pro-inflammatory signals, foods rich in polyphenols, which exert antioxidant and anti-inflammatory actions, have the potential to be harnessed as "anti-senescence foods" in a nutraceutical approach to healthier aging. We discuss the beneficial effects of polyphenol-rich foods in relation to the Mediterranean diet and the dietary habits of long-lived individuals, and examine their ability to modulate bacterial genera in the gut.

Medicinal plants with anti-inflammatory activities from selected countries and regions of Africa

Various nonsteroidal anti-inflammatory drugs have been shown to reduce pain and inflammation by blocking the metabolism of arachidonic acid by isoform of cyclooxygenase enzyme, thereby reducing the production of prostaglandin. Sadly, there are many side effects associated with the administration of nonsteroidal anti-inflammatory drugs. However, there are medicinal plants with anti-inflammatory therapeutic effects with low or no side effects. The Afri-can continent is richly endowed with diverse medicinal plants with anti-inflammatory activities that have been shown to be effective in the treatment of inflammatory conditions in traditional medicine. Interestingly, scientists have examined some of these African medicinal plants and documented their biological and therapeutic activities. Unfortunately, medicinal plants from different countries in Africa with anti-inflammatory properties have not been documented in a single review paper. It is important to document the ethnobotanical knowledge and applications of anti-inflammatory medicinal plants from selected countries representing different regions of the African continent. This paper therefore documents anti-inflammatory activities of various medicinal plants from different geographical regions of Africa with the aim of presenting the diversity of medicinal plants that are of traditional or therapeutic use in Africa.

Investigation of constituents from Cinnamomum camphora (L.) J. Presl and evaluation of their anti-inflammatory properties in lipopolysaccharide-stimulated RAW 264.7 macrophages

ETHNOPHARMACOLOGY RELEVANCE

Cinnamomum camphora (L.) J. Presl has been used for the traditional medicine as a therapeutic agent of inflammation-related diseases, including sprains, rheumatic arthritis, abdominal pain, cough and bronchitis, for a long history. The aim of the present study was to illustrate anti-inflammatory substances of C. camphora and their mechanism of action, and to establish the correlations between chemical constituents and traditional uses of this plant.

MATERIALS AND METHODS

Chemical constituents were purified by chromatographic methods, and their structures were established based on spectroscopic analysis. Lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages was adopted for evaluating the anti-inflammatory activity in vitro. The nitric oxide (NO) production assay and nuclear factor kappa B (NF-κB) dual luciferase reporter assay were used to screen anti-inflammatory constituents. The mRNA and protein levels of inflammation-related cytokines and enzymes were determined by real-time reverse transcription-polymerase chain reaction (RT-PCR), immunoblot analysis, and enzyme linked immunosorbent assay (ELISA), respectively.

RESULTS

Twenty-five constituents were isolated from the EtOH extract of C. camphora. Eight constituents, covering phenylpropanoid (7), lignans (10 and 22), flavonoids (16-18), coumarin (21), and terpenoid (24) significantly inhibited LPS-stimulated NO production with maximum inhibition rates (MIRs) of ≥ 80%, and thus were verified to be the anti-inflammatory substances of this ethnomedical plant. (+)-Episesaminone (SMO, 22) and 3S-(+)-9-oxonerolidol (NLD, 24) blocked NF-κB activation via inducing IκBα expression. Moreover, SMO and NLD inhibited productions of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and prostaglandin E2 (PGE2), and alleviated increased mRNA and protein levels of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX-2), and matrix metallopeptidase-9 (MMP-9) in LPS-stimulated RAW 264.7 macrophages.

CONCLUSIONS

The ethnomedical use of C. camphora for the treatment of inflammation-related diseases was attributed to the combined in vitro anti-inflammatory activities of phenylpropanoid, lignan, flavonoid, coumarin, and terpenoid. SMO and NLD were found to be new molecules with in vitro anti-inflammatory activities, which are achieved by inhibiting NF-κB regulated inflammatory response.

Structure-Dependent Modulation of Aryl Hydrocarbon Receptor-Mediated Activities by Flavonoids

Dietary flavonoids are used in treatment of multiple diseases, and their antiinflammatory effects in the intestine are due, in part, to interactions with gut microflora and possibly due to modulation of aryl hydrocarbon receptor (AhR) signaling. In this study, we investigated the structure-dependent AhR activity of 14 flavonoids in Caco2 colon cancer cells using induction of CYP1A1 and UGT1A1 gene expression as endpoints. A major structural determinant for AhR activation was the number of hydroxyl groups where pentahydroxyflavonoids (with the exception of morin) > hexahydroxyflavonoids > tetra-/trihydroxyflavonoids, and some of the latter compounds such as apigenin exhibited AhR antagonist activity for induction of CYP1A1. Simulations suggest that while quercetin and apigenin interact primarily with the same residues, the strength of interactions between specific AhR residues with CYP1A1 agonist, quercetin, in comparison with CYP1A1 antagonist, apigenin, is different; thus, such interactions are presumably indicative of potential switches for modulating CYP1A1 activity. The structure-dependent effects of the hydroxyl flavonoids on induction of UGT1A1 were similar to that observed for induction of CYP1A1 except that luteolin and apigenin induced UGT1A1 levels similar to that observed for TCDD, whereas both compounds were AhR antagonists for CYP1A1. Thus, the effects of the flavonoids in Caco2 cells on Ah-responsiveness and interactions with butyrate were both ligand structure- and response-dependent and these activities are consistent with hydroxyflavonoids being selective AhR modulators.

Flavonoids interfere with NLRP3 inflammasome activation

NOD-like receptor (NLR) family, pyrin domain-containing 3 (NLRP3) inflammasome is a component of innate immunity, and is responsible for producing mature IL-1β and -18. Several flavonoids were found to affect inflammasome pathway, but the mechanism of action is still obscure. To elucidate the effects on NLRP3 inflammasome pathway and to determine the structure-activity relationships, NLRP3 inflammasome in differentiated THP-1 cells was activated via treatment with monosodium urate (MSU) crystals. Levels of mature IL-1β, NLRP3 inflammasome components and apoptosis-associated speck-like protein containing a CARD (caspase recruitment domain) (ASC) oligomerization were investigated and the mechanisms of action were also elucidated. Among the 56 flavonoids initially tested, only flavone, 2',4'-dihhydroxyflavone, 3',4'-dichloroflavone, 4',5,7-trihydroxyflavone (apigenin), 3,4',5,7-tetrahydroxyflavone (kaempferol) and 3,3',4',5,7-pentahydroxyflavone (quercetin) significantly inhibited IL-1β production at 10 μM. Apigenin, kaempferol and 3',4'-dichloroflavone inhibited ASC oligomerization without affecting the ASC level in cell lysates. Apigenin also inhibited absent in melanoma 2 (AIM2) inflammasome-related pathway, but not NLR family CARD domain-containing protein 4 (NLRC4) inflammasome activation. The action of apigenin on NLRP3 inflammasome activation is mediated partly via inhibition of phosphorylation of spleen tyrosine kinase/protein tyrosine kinase 2 (Syk/Pyk2) pathway. Furthermore, orally administered apigenin (100 mg/kg) strongly reduced the number of neutrophils and monocytes in MSU-induced peritonitis in mice. The present study, for the first time, demonstrated the structure-activity profiles of flavonoids in NLRP3 inflammasome activation and mechanisms of cellular action. Certain flavonoids including apigenin are expected to ameliorate the inflammatory symptoms in autoinflammatory diseases associated with NLRP3 inflammasome activation.